Conductive and convective heat transfer systems for electronic displays are known. These systems of the past generally attempt to remove heat from the electronic components in a display through as many sidewalls of the display as possible. In order to do this, the systems of the past have relied primarily on fans for moving air past the components to be cooled and out of the display. In some cases, the heated air is moved into convectively thermal communication with fins. Some of the past systems also utilize conductive heat transfer from heat producing components directly to heat conductive housings for the electronics. In these cases, the housings have a large surface area, which is in convective communication with ambient air outside the housings. Thus, heat is transferred convectively or conductively to the housing and is then transferred into the ambient air from the housing by natural convection.
While such heat transfer systems have enjoyed a measure of success in the past, improvements to displays require even greater cooling capabilities.
In particular, cooling devices for electronic displays of the past have generally used convective heat dissipation systems that function to cool an entire interior of the display by one or more fans and fins, for example. By itself, this is not adequate in many climates, especially when radiative heat transfer from the sun through a display window becomes a major factor. In many applications and locations 200 Watts or more of power through such a display window is common. Furthermore, the market is demanding larger screen sizes for displays. With increased electronic display screen size and corresponding display window size more heat will be generated and more heat will be transmitted into the displays.
In the past, many displays have functioned satisfactorily with ten or twelve inch screens. Now, many displays are in need of screens having sizes greater than or equal to twenty-four inches that may require improved cooling systems. For example, some outdoor applications call for forty-seven inch screens and above. With increased heat production with the larger screens and radiative heat transfer from the sun through the display window, heat dissipation systems of the past, which attempt to cool the entire interior of the display with fins and fans, are no longer adequate.
A large fluctuation in temperature is common in the devices of the past. Such temperature fluctuation adversely affects the electronic components in these devices. Whereas the systems of the past attempted to remove heat only through the non-display sides and rear components of the enclosure surrounding the electronic display components, exemplary embodiments cause convective heat transfer from the face of the display as well. By the aspects described below, exemplary embodiments have made consistent cooling possible for electronic displays having screens of sizes greater than or equal to twelve inches. For example, cooling of a 55 inch screen can be achieved, even in extremely hot climates. Greater cooling capabilities are provided by the device and method described and shown in more detail below.
An exemplary embodiment relates to a front glass plate having a polarizer set in front of an electronic display so as to define an insulator gap between the front glass plate and the electronic display. The front glass may be set forward of the electronic display surface by spacers defining the depth of the insulator gap. The depth of the insulator gap may be adjusted depending on the application and environment in which the electronic display is used. The insulator gap may be anterior and coextensive with the viewable face of the electronic display surface. Because of the insulator gap the solar loading occurring on the front glass plate is not transferred to the electronic display surface.
Another exemplary embodiment relates to an isolated gas cooling system and a method for cooling an electronic display. An exemplary embodiment includes an isolated gas cooling chamber. The gas cooling chamber is preferably a closed loop which includes a first gas chamber comprising a transparent anterior plate and a second gas chamber comprising a cooling plenum. The first gas chamber is anterior to and coextensive with the viewable face of the electronic display surface. The transparent anterior plate may be set forward of the electronic display surface by spacers defining the depth of the first gas chamber. A cooling chamber fan, or equivalent means, maybe located within the cooling plenum. The fan may be used to propel gas around the isolated gas cooling chamber loop. As the gas traverses the first gas chamber it contacts the electronic display surface, absorbing heat from the surface of the display. Because the gas and the relevant surfaces of the first gas chamber are transparent, the image quality remains excellent. After the gas has traversed the transparent first gas chamber, the gas may be directed into the rear cooling plenum.
In order to cool the gas in the plenum, external convective or conductive means may be employed. In at least one embodiment, an external fan unit may also be included within the housing of the display. The external fan unit may be positioned to provide a flow of ingested air over the external surfaces of the plenum. The heated air in the housing may exit the housing as exhaust.
The first gas chamber may also act as an insulator for the electronic display. In outdoor environments, radiative heat from the sun is a major concern. As the surface areas of displays are increased the amount of solar loading also increases. To combat this solar loading the claimed invention provides a transparent anterior plate set forward of the electronic display. This area between the transparent anterior plate and the electronic display defines a first gas chamber. The gas chamber, as well as carrying away heat generated by the electronic display, also acts as an insulating barrier between the transparent anterior plate and the electronic display.
To further guard against solar loading of the electronic display, a linear polarizer may be employed at the transparent anterior plate. The linear polarizer serves to absorb a significant portion of the solar energy, in-turn reducing the solar loading on the electronic display. By significantly reducing the solar loading on the electronic display through he use of a gas chamber and the linear polarizer either together or separately, the temperature of the electronic display is significantly reduced. This reduction allows the cooling chamber to function more efficiently.
The foregoing and other features and advantages of the exemplary embodiments will be apparent from the following more detailed description of the particular embodiments of the invention, as illustrated in the accompanying drawings.